This invention relates generally to ferro-electric random access memory (FRAM) and more particularly to a hydrogen barrier liner for a FRAM chip.
FRAM chips are non-volatile memory cells and may include piezoelectric (PZT) material. PZT material includes lead oxide. The process used for manufacturing FRAM chips may include insulator depositions and metal depositions. Insulator depositions and some metal depositions may be hydrogen bearing processes. Hydrogen reacts with PZT material and deteriorates it by converting it to lead and water vapor.
FRAM chips may include tungsten, copper or aluminum wires connecting to electrodes of the FRAM chips. Tungsten contacts connect the copper or aluminum wires to a source or a drain. Etching the vias for contacting the FRAM electrodes creates a pathway for hydrogen by transporting along the metallurgy to reach the PZT material.
Reducing the exposure of PZT material to hydrogen during hydrogen bearing deposition and etch processes reduces the deterioration of the PZT material.